Grade 2 Long Neck Overlay Welding Flange

Grade 2 long neck overlay welding flange is typically used where corrosion resistance is more critical than high mechanical strength.

Compared with carbon steel or stainless steel flanges, the titanium structure eliminates internal corrosion at the weld transition zone.

The extended neck design reduces stress concentration and improves welding reliability in process pipelines handling acidic leach solutions, chloride systems, or mixed media environments.

This type of flange is often selected for retrofit projects where corrosion failure occurred in previous steel-based assemblies.

The long neck is not cosmetic.
It changes how the weld behaves.

Welding is moved away from the sealing face.
Heat influence is better controlled.

In corrosive systems, small defects grow fast.
Especially at the weld toe.

The extended neck reduces stress concentration.
It improves fatigue resistance in vibration conditions.

Bevel geometry can be adjusted based on pipe thickness.
Wall transition is smooth. No abrupt thickness change.

For overlay applications, compatibility with the base material must be evaluated.
Bolting material should also be reviewed in chloride service.

Acid Leach & Hydrometallurgy Systems

 

Used in wet acid environments where chloride and sulfate are present.

 

Common in nickel, cobalt, and copper extraction circuits.

 

Steel flanges often fail at the weld area first.
 

Pitting starts. Then leakage.

 

Grade 2 titanium is selected when corrosion stability is more important than strength margin.

Chloride-Containing Process Lines

 

Applicable where chloride concentration accelerates stainless steel corrosion.

 

Especially under warm, aerated conditions.

 

Long neck design improves weld integrity.

Less distortion near the sealing surface.
 

Desalination & Wet Scrubber Systems

 

Suitable for seawater handling and chloride-rich exhaust treatment systems.

 

Stable under continuous moisture exposure.

 

Better long-term reliability compared to coated steel solutions.
 

Long Weld Neck Design - What It Changes

Long weld neck is not a "shape option".
It changes the joint behavior.

The neck extends the weld away from the sealing face.
Less heat distortion at the flange face.
More stable gasket compression after cooldown.

The tapered transition reduces stress concentration.
Better fatigue margin under vibration and pump cycling.

For chloride / seawater service, small crevices become corrosion starters.
A longer neck makes the critical zones easier to control during fit-up and welding.

Discuss Your Application

Raw Material Verification

All Grade 2 titanium forgings are verified before machining.

Chemical composition checked per ASTM requirements

Oxygen, iron and hydrogen content reviewed

Material certificate EN 10204 3.1 supplied

Why it matters:
Interstital elements directly affect weld ductility and corrosion stability.

Dimensional Inspection

Each long weld neck flange is measured after final machining.

• OD / ID tolerance
• Bolt hole positioning
• Flange thickness
• Neck concentricity
• Bevel angle verification

Why it matters:
Misalignment increases weld stress and sealing distortion.

Positive Material Identification (PMI)

100% PMI available upon request.

Handheld spectrometer used to confirm titanium grade.

Why it matters:
Prevents material mix-up in multi-alloy projects.

Weld Area Preparation Control

Before shipment:

• Surface free from contamination
• No heat tint beyond acceptable range
• Bevel edges clean and uniform

Why it matters:
Improper edge condition can reduce weld integrity.

Optional Testing

Available upon request:

• Ultrasonic testing (UT)
• Dye penetrant testing (PT)
• Hydrostatic pressure test (assembled units)

 

Common tests

 

chemical composition

Mechanical properties

Appearance inspection

Individual Protection Before Crating

Each long weld neck flange is wrapped individually.

PE film for moisture barrier

Edge protection on sealing face

Bolt holes protected from impact

The flange face is never left exposed inside the crate.

For machined sealing surfaces, additional foam ring protection can be applied.

Internal Crate Arrangement

Long neck flanges are positioned vertically or separated by wooden blocks.

The neck section is supported to prevent bending during transport.

No direct metal-to-metal contact inside the crate.

For larger diameters, custom spacers are used to maintain load distribution.

Export Crating

Fumigated plywood cases

Steel band reinforcement

Moisture barrier lining if required

Each crate is marked with:

Heat number

Size

Pressure class

Gross / Net weight

Traceability

Every flange is traceable to:

Heat number

Material test report

Machining batch

Documentation is packed separately to avoid moisture damage.

Lead Time

Typical production lead time:

Standard sizes: 15–20 days

Custom neck length or special facing: 20–30 days

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